Class 12 NEET Physics Optics Questions Part 1

A real image is to be formed on the 2nd wall of the bulb placed on the first wall by the convex lens. The lens is placed at a distance of d from the 2nd wall.Now, we know that to form a real image of an object on a screen by a convex lens, the distance between the source and the screen (D) should be equal to 4f, where f is the focal length of the lens.
In that case, u=v=

D

2

=d.
∴ f=

D

4

=

d

2